1. Modern Automotive Technology PowerPoint for by Russell Krick
Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois

2. Chapter 47
Engine Tune-Up

3. Contents Engine tune-up General tune-up rules Tune-up safety rules
Typical tune-up procedures
Diesel engine tune-up (maintenance)
Engine tune-up (maintenance) intervals

4. Engine Tune-Up
Ensures that the engine, ignition system, fuel system, and emission control systems are within factory specifications
Recommended after a specific mileage
Refer to a service manual for the service intervals for all parts that require adjustment or replacement

5. Tune-Up Intervals

6. Minor Tune-Up
Performed on low mileage vehicles 30,000–40,000 miles (48,279–64,372 km)
Involves:
parts inspection
fluid replacement
filter and spark plug replacement
minor adjustments

7. Typical Tasks Visual inspection Check for diagnostic trouble codes
Replace the spark plugs
Check the ignition secondary components
Replace the air and fuel filters
Oil change and chassis lubrication
Emission control system service
Clean the throttle body

8. Major Tune-Up More thorough than a minor tune-up
Performed after prolonged use
Involves:
diagnostic tests
fuel injector service
carburetor repairs
distributor rebuild

9. Typical Tasks Perform a scope analysis
Test and replace the spark plug wires
Test and replace the fuel pump
Replace the drive belts and timing belt
Replace fluids
Adjust the valve train
Replace weak sensors

10. General Tune-Up Rules Gather information about the vehicle
Warm the engine to operating temperature
Calibrate the test equipment to ensure accuracy
Refer to a service manual and the vehicle’s emission control information sticker for specifications and procedures

11. General Tune-Up Rules Use quality parts Keep accurate service records
Lubricate hinges and latches, inspect belts and hoses, and check tire pressure

12. Tune-Up Safety Rules Wear eye protection
Set the parking brake and block the wheels
Place the transmission in park or neutral
Place an exhaust hose over the tailpipe
Keep clothing, hands, and tools away from moving parts

13. Tune-Up Safety Rules
Disconnect the battery’s negative cable when recommended
Do not touch hot exhaust parts
Keep a fire extinguisher handy
Relieve residual fuel pressure before opening the fuel system

14. Tune-Up Safety Rules
Disable the injection pump when removing a diesel fuel injector line
Read the operating instructions for all test equipment
Never look into a carburetor or throttle body when cranking or running the engine

15. Typical Tune-Up
Procedures

16. Preliminary Inspection
Battery—clean, no corrosion or damage
Air cleaner—filter, vacuum lines, and door condition
Belts—condition and tension
Fluid levels—oil, brake fluid, power steering fluid, and coolant
Hoses—condition
Electrical connections—condition

17. Air Cleaner Inspection

18. Spark Plug Replacement
Check the plug wire numbering and routing
Remove the wire from the plug by twisting and pulling on the boot
Blow debris away from the plug holes
Remove the spark plugs

19. Spark Plug Replacement
Read the spark plugs
normal brown to grayish-tan color
Replace the plugs (select the proper heat range and reach) and reconnect wires

20. Spark Plug Replacement
Use a spark plug socket

21. Spark Plug Replacement
Use a wire feeler gauge to gap the new plugs

22. Spark Plug Replacement
Start the plugs by hand to prevent cross threading

23. Oxygen Sensor Replacement
The sensors should be replaced at periodic intervals
The sensors become coated or fouled with exhaust by-products
Fuel economy and emissions are affected

24. Oxygen Sensor Replacement
Disconnect the negative battery cable
Unplug the connector
Use a ratchet and sensor socket for removal
Inspect the sensor’s condition
Coat the threads of the new sensor with antiseize compound
Start the sensor by hand and finish with a wrench

25. Compression Testing Checks the mechanical condition of the engine
It is impossible to tune an engine that is not in good mechanical condition

26. Adjustments Valve adjustment
mechanical (solid) lifters require adjustment
incorrect valve adjustment will upset the amount of air-fuel mixture pulled into the cylinder
the adjustment affects valve lift and duration

27. Adjustments Pickup coil air gap adjustment Idle speed adjustment
use a nonmagnetic feeler gauge to set the gap between the trigger (reluctor wheel) and the pickup
Idle speed adjustment
turn off all accessories
turn the idle speed adjusting screw on the throttle body or carburetor until the specified rpm is reached

28. Idle Speed Adjustment

29. Adjustments Ignition timing adjustment
disconnect the distributor’s vacuum hose where applicable
set the computer to base timing mode
aim the timing light at the timing marks with engine idling
rotate the distributor to change timing
refer to a service manual for procedures and specifications

30. Ignition Timing Adjustment

31. Diesel Engine Tune-Up
(Maintenance)

32. Typical Tasks Replace the air filter element
Clean, drain, or replace the fuel filters
Adjust the idle speed
Adjust the accelerator and governor linkage
Inspect the engine and related systems
Adjust the valve and injector timing
Change the engine oil and filter
Service the emission control systems

33. (Maintenance) Intervals
Engine Tune-Up
(Maintenance) Intervals
Specific periods (in miles or months) for component service
Given in the vehicle’s service manual